San Diego to Las Vegas road trip- sustained high RPM/angry bees

Discussion in 'Clarity' started by Vitamin P, Nov 28, 2019.

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  1. ClarityBill

    ClarityBill Active Member

    If the engine shuts off immediately when you switch out of HV mode, the rpm's are not above synchronous speed, and the reset will not work / help. The engine should be running, and continue to run, throughout the reset.
    insightman likes this.
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  3. Mark W

    Mark W Active Member

    Vitamin P,

    Thanks very much for posting the actual engine RPM, that was very helpful in knowing exactly what you experienced. I think different people use the term "angry bees" for different engine revving levels. As many people have noted, it seems like your car was operating as designed, but experiencing that high of a revving engine isn't pleasant. I know I don't like it the few times I've experienced it.
  4. Walt R

    Walt R Active Member

    I also took my car through the mountains last week, in this case Western Maryland and Pennsylvania. I also was seeing the power meter at 12 o'clock, and occasionally one major mark past it, to maintain 75 mph uphill. From another thread on here, I believe the 12 o'clock position represents about 90 hp. So, it would only make sense that if the ICE is trying to replace all the power being used, and the ICE has barely over 100 hp peak rating, that it will be operating at high RPM to produce 90+ hp.

    My new preferred technique for this driving is to switch to EV mode at the base of each hill, as the battery can easily produce the same 90+ hp without the noise, then switch back to HV at the top (where it stays in EV anyway) and regen and use HV until the next hill. Since the eastern hills are around 1000 ft individually (but often steeper than western roads), I only lost around 5 mi range on each while getting some back on the regen. I don't care about losing EV range as my goal is to arrive with no EV range anyway, and if it gets too low for comfort I can use HV Charge.

    OK, geek time: a 4200 lb car will gain about 1 kWh of energy by being raised 650 vertical feet. Which means, assuming around 4 mi/kWh, that it will lose 1 mile of range for each 150-200 vertical feet. So at a 3-4% grade, for each mile of horizontal distance, you will also lose another mile of range from elevation, costing 2 miles for each one forward. At 6-8% it will be 3 miles for each one forward.

    At 75 mph, which is 110 ft/s, on a 5% grade it will ascend 5.5 ft/s which will require 31 kW = 42 hp, which doesn't account for drivetrain losses or the power already needed to maintain speed against air resistance (probably greater than 25 hp). So, my observation of 90 hp seems to be within reason.

    If you see anywhere I messed up the unit conversions, comments are welcome.
  5. The Gadgeteer

    The Gadgeteer Active Member

    Sport mode, no HV, and stomp down on the go pedal. That gets me up the steepest hills no problem every time.

    The engine will start and rev up as needed. HV mode forces the car to try to maintain a certain charge level plus produce power to move the car so engine RPMs go up higher than HV mode off.
    Last edited: Dec 2, 2019
  6. When HV is engaged the car will attempt to maintain the current battery SOC. Regeneration will be restricted. Even though the car appears to be in EV, because EV is displayed on the dash, it is still in HV. Note the HV icon next to the battery gauge. If you want to maximize regeneration go downhill in EV.

    I recently bombed the northbound side of the Siskiyou pass in EV and witnessed EV range increase from 50 to 80 in just 6 miles. Of course, that reading is pure folly and the gauge only went up one bar. Had the batteries actually received that amount of charge in 6 minutes, they would probably be in orbit next to the Space Station.

    Did you mean to say that 1KWh of energy would be used or required to raise a 4200 lb car 650 vertical feet? Or have you discovered a way to generate electricity by raising heavy objects?
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  8. Walt R

    Walt R Active Member

    The potential energy is embodied in the car and its occupants, so yes, the car gains energy. I never said where that energy came from, so some other form of energy is being reduced, whether it is battery chemical, gasoline chemical, or kinetic (car slows down). Also, that calculation is the potential energy only, it does not include any losses from conversion from one form into another.

    Also, I have a hard time believing that Honda would avoid using regenerative braking just to maintain a (lower) SoC near the HV setpoint. I can believe the regen would be limited by battery temperature or already high SoC.
  9. Interesting perspective on energy. My observations are that the car loses energy on a regular basis. Either the stored energy in the batteries or gasoline. It needs to be fed more energy each time it is used.

    The rare exceptions are downhill sections. Run downhill a mile or six in HV, then repeat in EV while taking note of the change in EV range. It may not change your beliefs, but it should yield different results.
  10. JCA

    JCA Active Member

    You have to be a little careful about using the EV range number like that -- while it's pretty accurate for me on repeatable days/drives, it's not an absolute indicator of State-of-Charge. It's doing some sort of averaging of the last few drives or days miles/kWh with some "live" inclusion of the current drive, but it's kind of a mystery box of how each factor plays in. Steep up and down hills can definitely confuse the numbers coming out. My most memorable was descending from Sequoia NP with tons of regen; ended up with the EV gauge around 3/4 "full" and the EV range showing 55+ miles. Obviously once on the flat we didn't get anywhere near 55 miles on that 3/4 SOC.

    Using an OBDII device and app that logs the SOC itself would give better data; would be interesting to how closely it holds the SOC +/- some percentage in HV mode.
  11. craze1cars

    craze1cars Well-Known Member

    Obviously the car uses energy.

    But I think Walt's point is simply a unique thing about an EV, or a PHEV, or most any Hybrid frankly compared to an ICE vehicle...These cars have the ability to actually store and use gravity as a 3rd power source for later use.

    Coming down long mountain passes out of the Rocky Mountains in my Clarity I have gained a full 4 to 5 bars on the battery gauge by the time I reached the bottom, with engine off the entire time in EV mode...just by using paddles or brake pedal. I'm talking about some seriously long down grades that last 20 miles or more...that's where you really notice it building up in the battery and adding a very meaningful amount of electric range without using any fuel. But the car also does this on a smaller and less noticeable scale with every small downhill. And for that matter it stores a bit of inertia with every single stop, even running between stoplights on flat ground.

    That's one of the reasons those who live in substantially rolling country with lots of ups and downs will report a more substantial propulsion fuel savings over feeding a normal ICE powered car, when compared to those who live in the flatlands. Long flat interstate runs never allow the car to store potential energy. Hills allow it to do so repeatedly...saving propulsion fuel, whether electric or gas. And the ability of any hybrid to capture and store brake-friction for later use is the primary reason many are EPA rated at a higher MPG city number than highway number.
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  13. Yes, I take displayed EV range numbers with a grain of salt. Especially when I see it go from 50 to 80 on a six mile downhill and only add one bar to the gauge. 80 is a bit of an optimistic estimate for EV range and adding 30 miles of range in 6 minutes would require a charge rate that I’m reasonably certain Honda does not allow on this vehicle. I believe the gauge is more accurate.

    I believe you’ll capture more regenerative energy going downhill in EV, as craze1cars mentions above, than you will in HV. I have yet to see a gain of more than 1 bar on several descents of ~6 miles. That’s with the engine off. So why run in HV or HV charge when you can get the same or better results without running the engine?

    My observations in HV are that it will hold the EV range within 3-4 miles of the set point, even when going up a 6 mile, 6% grade. If there is an immediate descent I switch to EV for regeneration. If there is a stretch of flat or rolling terrain after the ascent I will remain in HV until reaching the descent. EV range typically recovers to the set point in a few miles. On relatively flat terrain, EV range will drop several miles on occasion and eventually recover to the set point.

    This is all using the wildly erratic EV range display. I have completed a 10 hour drive with more EV range displayed at the end of the trip than at the beginning, despite the fact that the battery gauge had lost 3 bars.

    It is a very enjoyable car and I’m beginning to think it will be even more enjoyable if I just ignore all this stuff.
  14. KentuckyKen

    KentuckyKen Well-Known Member

    FWIW, I’ve never felt the need to switch out of HV to get the most economical regen. Mine always shuts off the ICE at the first hint of regen when I’m in HV.

    And I’ve never gotten the angry bees going up a steep hill. Although that was at 60 mph with a full battery and with no passengers or heat, just AC.
    Either my Clarity is blessed with good behavior or I haven’t yet put enough load on it to stress it out.
  15. Mowcowbell

    Mowcowbell Active Member

    I agree with you Ken. No angry bees here. I think the main issue with getting the high rpm's is speed. Slow down. No need to try to drive 80+mph on a long uphill. If someone behind you doesn't like it, that's what the passing lane is for. It might gain you a few minutes, it might not. Can't put a number on how many times I catch up or even pass 'faster' drivers on the highway who get stuck at a light or make more stops than me.
    MPower likes this.
  16. craze1cars

    craze1cars Well-Known Member

    You aren’t driving in the Rockies on 1000s of miles long road trips with no charging opportunities. For normal hilly country on short day trips I agree with you because even in HV the car will shut off on a downhill. However this topic is about driving cross country, so I disagree In one circumstance, and that’s true mountain driving.

    For this type of trip crossing the continental divide it’s smart to remember that HV operates on a set point concept. If you’re coming down an actual mountain 10 to 30 miles downhill...steep...where you are going to gain several bars on the battery gauge, absolutely most would want to switch to EV until you get to the bottom, then reactivate HV so you can “save” that new higher set point for a later time when you may want to use EV crawling through small towns or whatever.

    But outside the super long mountain passes, I agree no point in pushing buttons and changing modes around while driving on a road trip. The car knows what to do and I just leave it in HV mode 98% of the time for long road trips. That holds true for the Smokies out East also...those aren’t really mountains so none of the downgrades are long or steep enough to actually fill a battery worthy of resetting your set point. I’ve only seen true opportunity to meaningfully recharge via gravity from the highest mountain passes of the Rocky Mountains. For smaller hills the car manages it better by just leaving it in HV.
    Last edited: Dec 5, 2019
  17. aaronj1159

    aaronj1159 New Member

    This is interesting for me, because here in the mountains of VA/WV, I've found that going up hills in HV Charge reduces the scream of the engine compared to HV/EV (post-forced into ICE use) by allowing the car to utilize battery range in addition to the engine. I suppose to describe it I'd say it acts similarly to what others are saying hitting the HV button twice does. My strategy is to use HV Charge going UP steep, sustained inclines (will eat some charge when available) and going back to EV to recharge on the downside.
    Walt R likes this.
  18. KentuckyKen

    KentuckyKen Well-Known Member

    Ah, now Grasshopper begins to understand. You’re not switching to get more efficient regen, you’re switching to reset to a higher set point. My limited HV experience and longest trip of 250 miles with no real mountains (just what you would call steep hills) has never put me in the situation you’re describing so you’re the expert here. I only lost 2 bars so I never had to change any thing.
    I’ll file this away and try it if I ever visit my sister out in Aspen CO and drive over Independence Pass.
    Again, this forum and it’s helpful posters are a never ending source real world observations and useful knowledge. Thanks.
    Last edited: Dec 5, 2019
  19. Cedar1

    Cedar1 New Member

    I have a sea level to 6000 foot climb from San Bernardino, CA to Lake Arrowhead. This climb is over the next 24 miles. I save my charge until I get to the bottom of the mountain. My range says 48 when I put it in EV mode. I do an aggressive climb without babying the car and when I reach Lake Arrowhead I have 2 miles of range remaining. I never hear the angry birds. My suggestion is to keep it in HV mode until those climbs and then go EV and back to HV. You may have to use HV charge at some point if your drive is a long one with many mountain passes.
    Walt R likes this.
  20. I’ll have to check “strongly disagree” on that.

    While I’ll refrain from using the term some use to describe the alarming sound of a 4 cylinder engine running at 4000-5000rpms, I have heard what I believe are those sounds while pulling a 6% grade at 55-65mph.
  21. To be clear, SB is at 1053’ above sea level and Lake A is at 5125’ above sea level.

    Does the ICE engage on this drive?
  22. But don't you lose more energy going up that hill then going down the other side? Assuming equality in both.
  23. We've had Angry Bees™ (lol) on level highways. Our recent trip to St. George Utah being one example. The engine had run for some time so we know it was warmed up. Driving the speed limit of 65 on a flat road in HV Sport the engine kicked in and ran like a banshee. After a few minutes I turned it off and back on and it calmed down, but was still running. We experienced this five or six times during the trip. Sometimes on uphill, sometimes on flat.

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